Description: Restored Phase Linear 4000 Autocorrelation Preamplifier in Excellent condition The 4000 Autocorrelation Preamplifier was a collaboration design by Bob Carver and Bill Skinner. It was designed to expand or decompress the sonics of recorded material. In audio parlance, it's called dynamic headroom. In the midst of all the knobs and toggles was the four channel balance joystick. The 4000 had the capability of controlling up to six components: a tuner, two tape decks, two turntables and an auxiliary input. It had three switched and three unswitched AC plugs. The 4000 was manufactured from 1973 to 1977. It retailed for $600 but the price rose 10 % in 1977. It's still highly sought after today. We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage. Special attention is paid to the power supply which is the most common source of failure for preamps. We then power up the unit and run a simple 1k sine wave while monitoring the low voltage output on an oscilloscope for signs of distortion or noise to get a baseline.At this point we will lubricate and clean all switches and potentiometers (that are not sealed) with a high quality contact cleaner, and then re-test all functions for any signs of noise or scratching. The following work has been completed;Repair of the autocorrelation functionTraced and repaired lans and solder joints where needed total of 15Final bench and test found to be working within factory specs Service fee $ 189.50 Sounds great. From a smoke free home 30 day warranty.
Price: 655 USD
Location: Marysville, Washington
End Time: 2025-01-21T00:02:20.000Z
Shipping Cost: 65 USD
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Item Specifics
Restocking Fee: No
Return shipping will be paid by: Buyer
All returns accepted: Returns Accepted
Item must be returned within: 30 Days
Refund will be given as: Money Back
Brand: Phase Linear
Type: PREAMP
Model: 4000
